Re: [PATCH v3 08/16] powerpc/pseries/svm: Use shared memory for LPPACA structures

[Michael Ellerman]

Thiago Jung Bauermann <bauerman@xxxxxxxxxxxxx> writes:
> From: Anshuman Khandual <khandual@xxxxxxxxxxxxxxxxxx>
>
> LPPACA structures need to be shared with the host. Hence they need to be in
> shared memory. Instead of allocating individual chunks of memory for a
> given structure from memblock, a contiguous chunk of memory is allocated
> and then converted into shared memory. Subsequent allocation requests will
> come from the contiguous chunk which will be always shared memory for all
> structures.
>
> While we are able to use a kmem_cache constructor for the Debug Trace Log,
> LPPACAs are allocated very early in the boot process (before SLUB is
> available) so we need to use a simpler scheme here.
>
> Introduce helper is_svm_platform() which uses the S bit of the MSR to tell
> whether we're running as a secure guest.
>
> Signed-off-by: Anshuman Khandual <khandual@xxxxxxxxxxxxxxxxxx>
> Signed-off-by: Thiago Jung Bauermann <bauerman@xxxxxxxxxxxxx>
> ---
>  arch/powerpc/include/asm/svm.h | 26 ++++++++++++++++++++
>  arch/powerpc/kernel/paca.c     | 43 +++++++++++++++++++++++++++++++++-
>  2 files changed, 68 insertions(+), 1 deletion(-)
>
> diff --git a/arch/powerpc/include/asm/svm.h b/arch/powerpc/include/asm/svm.h
> new file mode 100644
> index 000000000000..fef3740f46a6
> --- /dev/null
> +++ b/arch/powerpc/include/asm/svm.h
> @@ -0,0 +1,26 @@
> +/* SPDX-License-Identifier: GPL-2.0+ */
> +/*
> + * SVM helper functions
> + *
> + * Copyright 2019 Anshuman Khandual, IBM Corporation.

Are we sure this copyright date is correct?

cheers